The field of the present invention relates to magnetic storage devices and the use thereof in applications including memory systems, sensor systems, and logic systems.
There are two main means of storing digital information for computing applications: solid-state random access memories (RAMs) and magnetic hard disk drives (HDDs). Magnetic domains are the main scientific principle behind all magnetic storage ranging from the identification coded on credit cards, data on computer hard drives, and informations on storage servers. Currently all computer hard drives are essentially thin magnetic films covering a flat disk on which the data is written. Disk storage per unit space has roughly doubled every 18-24 months for about the past 40 years in accordance with Moore's Law. The primary force behind this growth has been the ability to read and write information using less space. However, the limits of this growth method are reaching an endpoint as the technological hurdle of reduced space limits the magnetic signal necessary for information retrieval.
New technologies and methods are needed to further increase disk storage per unit space. One potential technology is the use of patterned media meaning small, nanometer dimensioned, magnetic islands on the disk surface where each island could contain one magnetic bit. There is potential for increasing magnetic storage density using this approach. However the islands must be: (1) identical for reliability, (2) minimally spaced apart to keep the hits from erasing each other (based on interacting magnetic fields), and (3) kept large enough for thermal stability. Another potential technology is the use of small magnetic wires (nanowires) which could be grown three-dimensionally (i.e., vertically) creating new layers for data storage. However, fabrication of such nanowire systems in three dimensions has proven difficult.
New technologies for magnetic storage are desirable. Particularly desirable are magnetic storage devices which allow for the injection of magnetic domains using relatively small applied fields and dense packing of the magnetic domains in the storage device without the domains erasing each other (based on interacting magnetic fields).